In order to stably transfer audio, video, and other such data that requires real-time performance, a terminal that transmits such data ensures a sufficient amount of bandwidth before beginning a data transfer.
Patent document 1 discloses technology for ensuring bandwidth between a transfer-source terminal that transmits data and a transfer-destination terminal that is to receive the data, by transferring a packet for setting bandwidth to each relay device, in order, on the communication channel between the transfer-source and transfer-destination terminals.
Also, the IEEE 802.11e standard defines technology for realizing QoS control in a wireless communication system composed of a wireless control station that performs polling control and wireless slave devices that perform wireless communication in accordance with the polling control of the wireless control station (see non-patent document 1). The IEEE 802.11e standard defines a QoS control method that uses the HCCA (Hybrid Coordination Function Controlled Channel Access) control scheme. In HCCA, a wireless slave device can establish direct communication with another wireless slave device by communicating with the other wireless slave device using a predetermined protocol in accordance with transmission control performed by the wireless control station. This enables data to be transferred more efficiently than when the data passes through the wireless control station.
Patent document 1: Japanese Patent Registration No. 2995676
Non-patent document 1: IEEE P802.11e/D11.0, “IEEE Standard for Information Technology—Telecommunications and information exchange between systems—Local and metropolitan area networks Specific requirements—Part 11: Wireless Medium Access Control (MAC) and Physical Layer (PHY) specifications: Amendment 7: Medium Access control (MAC) Quality of Service (QoS) Enhancements”, October, 2004